摘要
采用光学显微镜、扫描电镜、透射电镜、X射线衍射仪和拉伸试验机等手段研究了预变形温度和预析出时间对7A20铝合金中第二相析出行为和组织性能的影响。结果表明:300~450℃预变形温度下析出的MgZn2相,粒子尺寸基本在0.1μm左右,400℃析出的粒子数量最多,分布更均匀。不同预处理制度下,合金在400℃保温2 h的预析出处理后,屈服强度和抗拉强度达到最高值,分别为170 MPa和310 MPa,同时伸长率也达到20%。拉伸断口均表现为韧性断裂特征。热轧形变和预析出处理后,MgZn2析出相衍射峰主要出现在40°~45°之间。试验合金1、2和4 h预析出处理后,MgZn2相的尺寸分别为0.1~0.2、0.3~0.8和0.6~1.0μm。第二相粒子密度随预析出时间的延长逐渐降低。
Effect of pre-deformation temperature and pre-precipitation time on precipitation behavior of the second phase,microstructure and mechanical properties of 7A20 aluminum alloy was investigated by means of OM,SEM,TEM,XRD and tensile tester.The results indicate that the average size of MgZn2 phase in the tested alloy is about 0.1μm,and the fraction of precipitation phase is the most and distributed uniformly when deformed at 400℃.The peak value of yield strength and tension strength of the alloy are 170 MPa and 310 MPa,respectively,after pre-precipitation at 400℃for 2 h,while the elongation reaches 20%.The fracture morphologies all exhibit ductile fracture characteristics.XRD peak of MgZn2 phase precipitates exists in the range of 40°-45°after hot rolling and pre-precipitation.The size of MgZn2 phase is about 0.1-0.2μm,0.3-0.8μm and 0.6-1.0μm after pre-precipitation for 1 h,2 h and 4 h,respectively.The density of MgZn2 phase decreases with the increase of pre-precipitation time.
作者
姜少婧
Jiang Shaojing(Yantai Nanshan University,Yantai Shandong 265713,China;National Engineering Research Center for Plastic Working of Aluminum Alloys,Shandong Nanshan Aluminum Co.,Ltd.,Yantai Shandong 265700,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2020年第7期78-82,共5页
Heat Treatment of Metals
基金
山东省重点研发计划(2019GGX102025)
山东省高等学校青创科技计划(2019KJA019)。
关键词
7A20铝合金
形变诱导析出
微观组织
力学性能
7A20 aluminum alloy
strain-induced precipitation
microstructure
mechanical properties
